this is by far the best explanation of how to use a LM317. None of the other literature i found gave guidelines and explained what happens when the Vin and Vout are wildly different. This video was awesome

@Afrotechmods

10 жыл бұрын

Gunhaver Thanks!

@photonic_induction2633

7 жыл бұрын

yeah just that 90 % of cheap lm317 dont like r1 to be 500r use a 100r resistor with 3k pot for 1.2 - 36v psu

I´m studying electronics in Germany and I really have terrible teachers, making my studies a nightmare... your videos literally made me refall in love with my job thank you a 1000´ times!

@mahantapradhan1177

3 жыл бұрын

M

The best electronics channel ever. You are above and beyond any other professional or educational provider. While there are professors and mentors I hold as exceptional, none have your personality. Whether deemed basic or intermediate+, your content is proficient and entertaining. Please do more.

I'm so happy you take the time to make these video's. I've been fighting with regulators [and feeling stupid the whole time, WHY CAN'T I UNDERSTAND!!!!] anyways..... Your videos have really helped me get a better understanding of electronics that my HIGH SCHOOL ELECTRONICS TEACHER couldn't even convey to me. I've been out of school for over a decade, and some of your topics have eluded me until now. Don't stop please, you really ARE helping THOUSANDS of people, if not millions!

@GNARGNARHEAD

6 жыл бұрын

how goes the hobby?

@bluetorch13 Watch my voltage divider tutorial video. In short, it's extremely inefficient to use a potentiometer to supply any more than a few mA. Also the voltage output won't be as reliable (hence "regulated")

@Intosia Ahhh... well depending on the feedback resistors used in the design you may need to put a small load on the device for the output voltage to be stable. So yeah measure it with a 1k load or so.

you sr, are my inspiration. i think i told you before. i had done nothing with electronics, till one day i started soldering. i searched the web for information and you came up 100% of the time. and i tell you what. i would recommend you over any electronics class. thank you for teaching me a new skill. :)

Thanks for taking all the time and extra effort to produce such high quality, easy to understand video tutorials. Hopefully more are coming.

@L1ne3 No - as I recall it's from a 50uA bias current. So just do (50x10^-6)xR2. 3.3uF is fine.

You are one sharp cookie who knows what you are talking about! I like your style for I need to design a fixed voltage power supply. I can tell you are a college teacher. From one scholar to another, I appreciate your knowledge and your teaching mode. Keep up the good work.

Thanks! Works great with a computer power supply. Since a cpu power supply has -12v and +12v and voltage is equal to the difference, you can use the -12v as the ground instead of a 0v ground and get a variable 24v.

I've used the LM317 and 337 (for split rail power) in a power supply I made, easy parts to work with and quite reliable.

@nlimchua That is the approximate adj current shown in the datasheet.

@Shaunakde Yes, but LED supplies are switchmode constant current supplies whereas normal DC-DC converters output a constant voltage.

@catatonicprime lol... the script for this video has been like 6 months in the making... totally forgot to update that part.

@Intosia Hah! I'm an idiot for forgetting to talk about this. Basically you should hook up your multimeter to the output, measure the voltage, and make adjustments accordingly. Once you've got the voltage you want, connect up your load.

I love the humor you stick in your videos. You keep them informative, but not dry, Thank you for posting. Things like "Lines = heat not spider sense", or "Let's not be blowing headphones" on another video.

A nice, clear and understandable video on LM317 Adjustable Voltage Regulator. Thank you for posting such valuable content !

@KIBProductionz Any voltage regulator IC will be better than a zener. The zener voltage can easily vary by +/-10% over their full current and temperature range. Sometimes that's good enough though.

Afrotechmods: The best educational videos, very professional, these videos make you wish to learn more and more, this man knows how to teach electronics, is awsome.

Miss you, man! You have been my all-time favorite electronics KZreadr. Mr. Carlson's Lab is my number two fav. But I still really miss you!

@Afrotechmods Thanks!! I'm planing on starting to build LED drivers. Your vids are more than excellent.

Thank you so much, no one else was able to provide this info in 2024, so crazy

I just subscribed, simply because I love how you explain everything :)

Thanks again: I'm binging out on your tutorials today: great video!

This Afrotech guy is the best.... I wish I had professors as good as he is. Two thumbs up for ya !!!

I love how all of your clips are singed haha. Great videos by the way, very useful for an EE student like me.

Good to see that you are back and making videos. I really enjoy them! Would you consider making a video on DC to DC converters???

after realizing I had everything back wards it is now working :D thank you

I have a dream where gifted people just like you post videos easy-explained just like yours teaching a circuit with voltage and current regulator with potentiometer. Maybe one day!

Thank you for the tutorials. When I calculate the current through R1 and R2 do I use the input volts or the output volts. I especially want to get a variable pot with the correct watts. Thanks.

Hey Afrotechmods, Good video. The LM317 works as a variable power supply but the heat dissipation issue to me kinda limits it usefulness to only a couple of volts. You would need a massive heat sink, preferably with a big ass fan if you wanted to run it at 3 volts with a 12 volt or greater supply voltage. I think a fixed linear or a SMPS would be a better option. They are o.k. as far as learning to use one, but I think I'll stick with linear for now, not very often do I need a variable supply. Take care, C.

@ClownWhisper

2 жыл бұрын

I don't understand the equation to figure out resistance. I want to generate 3.3 volts from a 4.7 Volt 18650 or maybe a lipo battery what would the equation be because I did not understand the way he described it

@ClownWhisper

2 жыл бұрын

Holy **** I just realized how long ago you posted this sorry LOL but since I already asked the question I like to add I know that five volts would be a lot easier I could just use in 7805 but I'm trying to minimize voltage and current draw for this tiny circuit then I'm building I'm trying to make it as efficient as possible. I know I could run it off a buck converter but all I have or some really ****** Chinese ones that are flaky as all hell and I don't wanna risk it

Very good information...perfect mix of information, technicals, and wit!

I learned more watching this video than my house wiring class. Thank you!

Hi Afro, Great video and easy to learn with your clear straightforward videos. I will be sure to link to your Amazon.com page in the future. Glad to do it .! Cheers, G.

This video filled my needs so perfectly

@bananastalktome oops... copy and paste error! You are right.

Best tutorial for make variable source

This is great and really easy to understand, especially when trying to learn electronics yourself.......thanks

Thank you. This is very easy to understand.

that is one cool theory video. the owon and the fluke are sweet! i will feature it these days in my site for sure. keep it going.

As usual another excellent video. Please make more!!

Awesome video! What would be the next-best alternative to a linear voltage regulator if you were looking for something more efficient?

Thanks for a great video! Been checking your channel every day :)

@reactor1system Use a diode+very large capacitor to have a more stable voltage on the input before the LM317. Or buy/build a SEPIC DC-DC converter.

Awesome and clear - Thanks!

Excellent video, had an LM317 lying around and was trying to figure out how to use it and was wondering why the voltage was never varying even when I checked the datasheets. Never added a R1, since I thought I didn't needed it(and never paid attention to the equation in the datasheet).

Awesome video as usual! Thanks for posting this.

Your vids are deeply appreciated. Thanks👍

prime vid man. I just borrowed "Electricity (1882) from the library. Taking myself to school on all things electrical, magnetism included. Keep the vids comin i hope to have an intelligent question to ask you in the future lol

Do you prefer voltage regs like the 7812 etc. to Zener diodes?

Nice tutorial! Clear and easy to understand! I do have a question though: I have two lead acid batteries in series to get 24V+ but my motor controller doesn't like variable input voltages so I need to stabilize the voltage from the batteries to 24V. The motor can draw about 5 to 6 A max at 24v, 1 to 2 A continues. I have found a mosfet, like your LM317, the TIP14x, its data sheet specifies that it can handle up to 10A continues and 20A peak. Can I use this mosfet in your setup without problems? Or do I need to use a different circuit? Thanks!

Great video as usual, good teaching. I've use this chip before but never paid attention to the inefficiency calculations. Can you going to make a video on the more efficient yet more complected switching regulator? Thanks Again for all of your videos!

Really good video, as usual!

Thanks, I really should have known that,I saw that later also explained on another video. Most videos neglect that part of the equation, they say because the difference it makes to the outcome in most instances is miniscule.

Useful video, although as with most others it makes lots of assumptions that will cause many viewers confusion, and it also demonstrates some basic errors. The LM317 has certain requirements for best operation, and one of these is a minimum current into the ADJ pin.....as I recall, 240 Ohms or thereabouts is the maximum recommended value between the 317's OUT pin and the ADJ pin to keep the ADJ current within recommended limits. Secondly, if you want an adjustable regulator, you keep the resistor between OUT and ADJ constant and adjust the resistance between ADJ and ground; this video suggests the opposite, and while it will work that way after a fashion, it is not good design practice and can cause problems. Finally, a 1uF (one microfarad) tantalum (not electrolytic) capacitor is recommended between the OUT and ground to prevent oscillation as the regulator tries to keep the OUT voltage constant; this has nothing to do with reducing ripple (as from a regulator having an input derived from a rectifier coming from an AC supply), it is just there to improve stability of the IC. Then, for the math-challenged folks, the simplified formula for calculating the OUT voltage on an LM317 circuit is V-Out = 1.25 x (1 + (R2 / R1)), where R1 is the resistor between OUT and ADJ, which is usually fixed at 240 Ohms, and where R2 is the resistor between ADJ and ground. Note that ground itself is not connected to the LM317. But to find the resistors required to achieve a desired fixed output voltage, you switch the formula around like this: R2 = ((V-Out / 1.25) - 1) x 240 this assumes that R1 is fixed at 240 Ohms Example: If you want the OUT voltage (V-Out) to be 7.2V, and you fix the R1 value at 240 Ohms, then you solve as follows: V-Out / 1.25 is the same as 7.2 / 1.25 or 5.76 then do the part where 1 is subtracted from the previous intermediate value 5.76 - 1 = 4.76 then multiply the new intermediate value of 4.76 by 240 (same as 4.76 x 240) = 1142.4 this can be rounded slightly to 1142, which is the R2 value in Ohms, more commonly represented as kilo-Ohms, or 1.142k Put the 1.142k resistor in the LM317 circuit in the R2 position. Don't have a 1.142k resistor (it is a non-standard value)? Well, a 1.2k (1200 Ohms) is a standard value, and nearly the same.....if you stick it into the R2 position in the original formula V-Out = 1.25 x (1 + (R2 / R1)), it will look like this: V-Out = 1.25 x (1 + (1200 / 240)) solving in stages: V-Out = 1.25 x (1 + 5) V-Out = 1.25 x 6 V-Out = 7.5 Not close enough to 7.2 volts to suit your needs? Then you need to add smaller value resistors to add up to a value closer to 1.142k, or you need to use a slightly smaller value (perhaps 1k) resistor in series with a small value potentiometer (usually you pick a value twice what is needed, so if you are making 1.142k out of a 1k resistor plus a potentiometer, then the difference between 1.142k and 1k is 142 Ohms, and doubling that gives 284 Ohms, so you might get the closest standard potentiometer value of 250 Ohms, set it to roughly mid-range, and make small adjustments from there until the LM317 puts out exactly 7.2V. This arrangement of a large fixed resistor value in series with a smaller potentiometer allows you to use the potentiometer to easily trim the overall resistance value up and down by the same amount, and since the potentiometer is not making up ALL the resistance, you have better selectivity doing it this way. The other thing to remember is that, as the video mentions, the LM317 (like all linear voltage regulators) gets rid the the extra voltage (the difference between the input and output voltage) in the form of heat. When the current coming out of the regulator to your load is more than a hundred milliamps (mA) or so, that dropped voltage times the output current comes to more wattage (in the form of heat) than the LM317 can get rid of by itself, hence the need to add a heatsink.

@j5892000

5 жыл бұрын

Ah ok. I was wondering about. The resistors. Do the regulators work with ac or just dc?

@YouCubeHD

5 жыл бұрын

when masters speak :)

@deadalpeca8099

5 жыл бұрын

@@j5892000 this particular regulator works for dc only (typically an input of 2-47v I think, check the datasheet). If you have an ac output then rectify it using diodes (a single diode with a capacitor will do the job for small voltages but a full bridge rectifier is better for higher voltages of ac)

@howitza4

5 жыл бұрын

Oh wow, I appreciate you so much :) Could of caused me a world of hassle if i didn't have a read of the comments. May have been 3 years since you posted it, but these are the gems that are hidden away in the depths of youtube.

@lloqalla

5 жыл бұрын

I am agreeing with Alf, this is great - the combination of a video maker with the motivation to do the video even with some rough patches, plus some extra hints and course corrections from a clever person like Youtuuba, is pure community genius --- thanks to both of you (I note that the circuit diagram shows a 240 ohm resistor....)

you are amaaaaaaaaaaaaazing , thank you sooooooooooooo much for the explaining.

Nice tutorial and very well explained.

I love you Afroman!

This is an EXCELLENT video. Thanks a lot

"This is a very common way to ... see how many volts it takes to blow something up!" Laughed out loud; a nice piece of humour in a very informative video.

Am I the only one who notiiced Mr T at 0:40? :D

About my case bellow... After a lot argument that the 317 needs 100-120R as R1 to meet the minimum current and Pot as R2 which for some reason was not regulating the Voltage at least without Load,i decided to SCREW the minimum current and add a Fixed R2 and a Potentiometer in Series to 100Ohm resistor as R1 and BINGO! Bingo boys,3 nights in a row and my first thought worked better,but the nights were still gone. I really should have got another Regulator like LM1084 which i know inside out.

I like your explanation, good job.

Thanks dude, really helped me!

Thank you so much. Your videos are greatly appreciated.

Thanks for making this videos. I appreciate your effort ;).

thank you for this great video .. i have problem if you can help with .. it's getting to high temperature when i use it to control my 12v soldering iron voltage.. any suggestions or different solution for high loads ?

excellent video! congratulations. i will feature it in my site today

Great explaination, does this apply for the LM338 also with no required modifications to the circuit? People tend to use diodes and capacitors can you help explain their purposes in this circuit and what you would recommend.

Thanks for the good electronics instructions, they are very helpful. Wouldn't the 1/4 watt resistor you had hooked up there fry, if you used the power supply to supply a 7.8 watt load?

@superTransformer99 It's worth trying. If you put 0.1 ohm resistors on the output of each regulator then tie the other side of the resistors together it will definitely work.

super nice tutorial. thanks.

@oM4rE7 yes

i just wanna say THANK YOU very helpful

u r a good communicating teacher

Awesome. I need to step down the viltage (5v to 3.3v) coming from a development board into a wii chuck and I just happen to have one of these ICs lying around.

@SirArghPirate Sure, but the most important thing is to not overdischarge lipos, or overcharge them.

Neat. I'm actually very glad you made this video now. I just subscribed to your channel a few days ago and I was pleasantly surprised to see this because I am about to build a solar 4 AA Battery charger using this component. Good timing and thanks! One thing I dont really understand is .. why do you need two resistors? Is the "Adjust" pin like an input type or output type? (Which way is the electricity going there?) Why do I need a resistor from output to adjust? Cant I just have one on ADJ?

wow, thanks , great video. one question, if the volts are exactly what i need , but im putting out about .5 amp too much can i reduce the amps with a resistor?. if so do i use ohms law to calculate the size of resistor?

Good easy to understand tutorial..thanks

How would that circuit look on a PCB I'm building a circuit similar to that but also has a 3 volt DC motor SPST Switch it's to control a camera mount like a telescope. I want to do a etched PCB but not to sure how to lay it out oh by the way I'm a newbie at electronics.

@kapoutkapoutmapout

6 жыл бұрын

Afrotechmods will it work with lm317

Thanks sir for giving us such a nice video on lm317t........Thanks

@pcbheaven Thank you!

Awesome video Sir. Thank you :)

Thanks for this videos, they are very informative! I just have a question. When i search for this regulators, I see that the datasheet have a current after the regulator voltage. For example, a LM7815 says 1A and a LM78L15 says 100mA. What´s the difference?

i want to make a 7.5 volt power supply with 1A from a 12 volt power supply with 20A, with the lm317. what would be the values of the resistors R1 and R2? Thanks

thank you so much. :D I made ​​one, I just followed this video

@meade9166 LM150

Thank you for this instructional video. I have a question. I need a step-up regulator that converts 3.7V to 9V. How can I get it?

@Afrotechmods Thanks for the reply and info. And chance you'll make a video on one of those?

very well described thank you.

I made my own voltage regulator on my own with LM317T . It was easy to make.

Excellent video. Thanks.

please upload more videos about electronics ... thank you very much :)

thanks it help out with my homework XD, great videos

I have no idea what you're doing but it's great stuff.

Hey, great video. I have a question you may be able to help with. I'm doing an RC wheel chair mod and I need to get a 6v power supply to output 2.5v positive AND 2.5v negative. Using the LM317 and various resistors i'm able to get the positive current right in the butter zone but the negative is always around -3.8 or so. Would you have any suggestions on what I would need to regulate the negative current and how to do that? Thanks!

Hello i made this voltage regulator as per your diagram, bit of fault tracing and repair at my end, but works perfectly. My question, is there a voltage regulator that can control from 0.5volts or less, maximum volt i need is 5 volts. Great video's i have only subscribed to two channels and one is my daughter

thankyou. i needed this regulate my computer fan speeds